A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that instance, a patterning device, e.g. a mask (reticle), may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g. including part of, one, or several dies) on a substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned.
An electrostatic clamp is a clamp that operates to clamp an object using electrostatic force. Such a clamp may be used in a lithographic apparatus. For example, a lithographic apparatus using extreme ultraviolet (EUV) radiation or electron beam radiation may operate in certain regions under vacuum conditions. An electrostatic clamp may be useful to clamp an object in such regions. An electrostatic clamp may be provided to electrostatically clamp an object, such as a mask or a substrate (wafer) to an object support, such as a mask table or substrate table, respectively.